View Full Version : Fan PCB Speed To High

09-08-2014, 05:40 AM

I finished my build in a Enthoo Pro. I plugged all of my fans into the fan PCB and connected the 4 pin to my CPU fan header on my motherboard (Asus Sabertooth 990FX).

I connected the sata power connector. However when I go into the bios and set the fans to 60C 100% duty cycle and 30C 20% duty cycle, the fans will not go below 1000 RPM. Full speed on these fans is 1200 RPM. I've tried using Asus fan Xpert and no matter what I set it to it will not drop the fans below 1000 RPM.

If I drag the little graph around on fan Xpert the speed of the fans do change they just won't go below 1000.

How can I get them to go lower? (if I voltage control these off a fan header they will go as low as 500 RPM).

Is it my motherboard's fault? Am I doing something wrong? These fans are still way too loud for my taste at 1000 RPM.

Thanks for any help!

09-08-2014, 11:10 AM
I don't have an Asus board so can't really be much help. Maybe up the max to 70c or 80c@100% or set min to 40c@20%, or maybe both.. and see what that does. I have heard not to use the automatic fan setup thingy in Fan Xpert. ;)

09-09-2014, 03:21 AM
Hi doyll,

I just tried setting the max temp to 70C @ 100% and 40C @ 20% i even tried setting it to 50C @ 20% and even both high and low temps to 20% nothing makes them move below 1000 RPM.

In Asus Fan Xpert when you click test it turns off the fans and then brings them up from 0 - 100% the lowest setting in which the board allows is 20% and according to Fan Xpert, 20% = 1080 RPM. And 10% = 980 RPM, but the board won't allow a setting below 20%.

But that doesn't make any sense because how can 20% be 1080 RPM on a 1200 RPM fan?

I really don't understand how the PCB works.

Maybe ASUS lies about being a real PWM signal?
I know most motherboards have an option to select either DC or PWM control.
This one does NOT have that option it just has Q-Fan On/Off then Standard/Silent/Turbo/Manual.
if you set it to manual it asks for a high temp and a low temp as well as a duty cycle percentage.

And if you set it to anything other besides manual the fans will spin at full speed.

Edit: I tried another fan this fan has a max RPM of 900, when I use the 20% setting, I get 750 RPM.
Seems like no matter what fan I connect at 20% setting it only slows down by 200 RPM. I don't have enough fans to swap to slower fans so I'm hoping there is a way to slow these 1200 RPM fans down. There aren't enough fan headers on the motherboard to just switch to using voltage control so I am kind of hopeful there is some way to use the hub still.

09-09-2014, 06:24 AM
I have seen this same problem several times now, but have not followed up to see if anyone got it sorted.

Seems there is someting about Fan Xpert test notworking properly with the Phanteks PWM controlled fan hub. Something about the delay in speed changes and reading that Fan Xpert needs to do it's thing. Not sure if anyone has figured out how to get it all working properly. With my old X58A-UD5 and UD3R boards the hub works great. Sorry, I know that's no help for you. :(

09-09-2014, 08:52 AM
Thanks for the helpful info at least.
I figured it might be the boards fault because the bios has very few options for fan control.
So the only way to really do much is the Fan Xpert software. :(
It would also seem that Asus has given up on this model seeing as the last bios update was in 2012.
So it would seem there is little hope for Asus to provide a bios update with improved fan functionality.

09-09-2014, 11:53 AM
Did a little digging and found this about Z87-A boards:
Post #1

I have a problem with the Asus Fan Xpert 2 software (part of the AI suit 3). I can control the 3 PWM case fans, but I cannot control the CPU fan through the software. While the software is installed, the CPU fan is always running at max speed. The speed-temperature graph through which you control the fan speed at different temperatures is grey, and I cannot change the speed of the fan in any way. However, I can see the RPM of the fan.

I've tried running the auto tuning from the xpert multiple times, but nothing changes. It does recognize the case fans and modifies their speed graphs, but the CPU fan remain at max speed all the time.

I can control the CPU fan speed through the bios just fine, so its not a hardware issue. However, the Fan Xpert overrides the Bios settings, so even if I modify the fan speed at the Bios, as soon as I go to windows the CPU fan is back to full speed.

I had to uninstall the fan xpert, and disable the asus fan control service, to prevent the CPU fan from spinning at max speed all the time. Now the fan's speed is dependent on the CPU temperature, as it should be.
Post #5

I installed the fan xpert again (since I couldn't find the option to install/uninstall only part of the software, I had to uninstall all the performance utilities of the AI suite to uninstall the fan xpert), but did not run the fan tuning, and now I can control the fan again! But as soon as I run the auto tuning, I lose all control of the CPU fan, and it continues to spin at max speed at all times.

The only way to gain control again is to reinstall the fan Xpert, and not run the fan tuning.

Apparently the problem is in the auto tuning part of the fan xpert.

09-10-2014, 06:12 AM
I tried using another motherboard I had lying around this time a MSI motherboard, And its doing the same thing. I plug the fan hub into the CPU fan header, turn on smart fan mode adjust the graph to be 12.5% at the lowest spot. And it still only lowers the fans 200 RPM. From 1300 to 1100. Am I not using the hub correctly? Is the hub faulty? I'm really getting frustrated.

Edit: MSI's fan settings in the bios are horrible on this board too. I set the target temp for 70C which results in a ~1100 RPM setting, I tried using MSI's command center software and I get the same result. Nothing seems to allow it to drop below this magic 1100 RPM.

09-10-2014, 06:53 AM
Try raising the target temp and see if that makes them slower, I'd try 85. The MSI fan control apparently is not reading the sensor correctly. You should only have to adjust the header the hub is plugged into. That header should run the whole hub. You didn't connect the 12V plug did you?

09-10-2014, 09:13 AM
Yes I did connect the sata plug, I was under the impression you should as thats what the manual states to do isn't it?
It said something like if you're using the CPU fan header, connect the 12V if you're using any other header not to.

Am I not supposed to? How many fans can my header power without damage?

I can't seem to find anything about it.

Asus' Manual States 12W / 1.0A for the fan header.

I'm running 4 120MM fans that are 1.08W each or 0.09A and 3 140MM fans that are 1.2W each or 0.1A. So if my math doesn't totally suck, thats 7.92W of fans or 0.66A

Should be ok right?

09-10-2014, 10:15 AM
As I understand it, and the way I have mine hooked up, if you connect the 12V sata header, you can't control the fans, they will run a 100% because they are running from the sata header. If you disconnect the 12V sata plug and just use the PWM cable from a motherboard PWM header to port #1 on the fan hub, however you set that pwm header that the fan hub is connected to, will control all the fans hooked to the fan hub by that setting. I think I got that right.

I have the stock case fan connected to the fan hubs, so 3 X 140mm fans. The rad fans are on a fan controller.

09-10-2014, 10:30 AM
I tried disconnecting the 12V the lowest i can get it to go is still 1100 RPM even without the 12v being connected. Same result as having the 12V connected.

Thats with setting the temp target to 80C

09-10-2014, 10:50 AM
Well, maybe it is not a true PWM header. Some of the new boards, I hear, have 4 pin headers that are called PWM, but they are not. I can't say that for a fact, but I have heard that. I only know that is how mine is hooked up and it seems to work fine.

If you have it connected to the CPU fan header, that is the only header you need to set. Try just making your setting to the 4 pin PWM header you connected the cable from the fan hub to the motherboard. None of the other headers will affect it.

09-10-2014, 11:14 AM
Neither of the two boards i've tried seem to be able to control it, neither board have anything in the bios allowing me to pick DC or PWM mode, they just have "Smart Fan" or "Q-Fan". However both are listed in the manual as being PWM. Not sure what to do at this point.

Edit: I do want to say If I connect a 4 pin fan to the CPU header it controls it just fine.

09-10-2014, 11:59 AM
PWM fans can be controlled by both PWM signal and 12v power or variable voltage control, so just plugging in a PWM fan does not determine if there is a PWM signal.

09-13-2014, 04:15 AM
I would think its probably another dud Phanteks PWM controller. I had the same issue on mine and after much testing etc, I asked for a new one to be sent to me and everything is A OK now. Using speedfan to control all my fans with PWM control and everything responds as it should!

09-13-2014, 08:46 AM
That is a definite maybe. :D

I've had no problems with mine, and most problems people have are from motherboard, but I'm sure a few have been and will be defective. Quite a few bits in these hubs, solder joints, wires, plugs, etc.

03-05-2015, 07:15 PM
If you connect the fans from a 4 pin Z87 header and connect it to the hub with the SATA / Molex power connector, they will run at full speed. That is because either peeps assume 4 pin "means" means PWM or the manual erroneously states that it is PWM. While they can control PWM fans, they do it with DC voltage.

DCV control takes place by varying the voltage from the header to the fan.

PWM control works by ALWAYS sending 12v to the fan but by increasing / decreasing the interval between when the signal is ON or OFF

If you are connected to a header which is supplying variable voltage, the connecting a 12V supply to the header overrides the less powerful variable voltage signal.

With Zp7, headers can be set to either DCV or PWM control so make sure the BIOS setting is appropriate

I am using fanXpert to control 3 hubs connected to CHA_1, CHA_2 and CHA_3 ... works extraordinarily well.

03-10-2015, 10:37 AM
I am having the same issue controlling my fans with phantecks case and asus motherboard...wondering if you solved your issue?

03-10-2015, 03:09 PM
What header are you using to supply PWM signal to the PWM controlled hub? It will not work properly without a PWM signal.